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Topic: Cable help - MixPre to M10 (Read 5699 times)

Hello, I'm not a taper of gigs but I do sound recordings for films and some narrative stuff for micro budget short films too. I have been using a Sound Devices MP-1 into an M10 via a cable I had made for me here in Australia. The cable is female XLR to male dual mono 3.5mm. The guy who built my cable said splitting the signal would provide a small amount of attenuation that would help going line in on the M10. The cable has worked well seeing as what I record is fairly tame.

I have a d50 for stereo recordings and decided I wanted something better quality with a lower noise floor so bought a used MixPre and have an Audio-Technica BP4025 on the way.

I assumed I would be fine using a short mini-jack cable and go from tape out on the MixPre to line in on the M10. I am, however, experiencing very low levels using this configuration. For narrative work and for nature recordings I have to max out the gain on the MixPre to get barely useable levels. Sony M10 is set to 4.5, low sensitivity. If I use the mic in on the M10 instead I get much better levels.

Question is, should I use use tape out to mic in, tape out to line in, or line out to line in with my custom cable, or should I have a padded cable made to go from line out to line in?

I hope it is ok to ask for help here. Not many people are using this combination on filmmaking forums and I understand many member here use the M10.

1. First use the 3.5mm consumer line level out (it is labelled tape out) of the MixPre-D > 3.5mm line in of M10

2. Then turn on the tone oscillator/generator of the MixPre-D

3. Set your M10 to REC Pause with 24-bit depth/rate.

4. Calibrate the record level of the M10 to -20 dBFS (this is the unity gain)

That's it, easy as pie you are now properly calibrated!!!

The MixPre-D & MixPre do not use the same 0 dBFS that your recorder uses so 0 dB VU on the MixPre-D is equal to -20 dBFS. Think of this as similar to converting inches to centimeters or fahrenheit to celsius. Different Scales for the same purpose. +20 dB VU on the MixPre-D or MixPre is also equal to 0 dBFS. It is like the K-System K-20/RMS scale of metering allowing a wide dynamic range 20 dB of headroom...

Thus, it is perfectly okay to exceed 0 dBu on the MixPre-D or MixPre unlike the recorders 0 dBFS.

This MixPre-D image shows the tone oscillator/generator turned on (the [~]/SLATE switch)

This image shows proper meter calibration of MixPre-D to Sony M10It is perfectly fine to run the your levels over zero on the MixPre-D. Remember +20dBu is equal to 0 dBFS when properly calibrated, run your levels accordingly.

I have the MixPre, not the MixPre-D. MixPre only has tape out and line out.

I know how to use the tone function. I understand reference levels. If I calibrate the levels on the m10 to -20dbfs (around 4.5 on m10 gain wheel), I am having to crank the gain on the MixPre to full in order to get something approaching useable levels, even if my mic is one foot away from my mouth and I am talking loudly.

If I crank up the m10 gain I am raising the noise floor and I can't have that for recording dialogue and especially not quiet nature recordings.

I appreciate your help but you are both missing my question. I understand reference levels. I understand tone generators and how to use them. I understand calibration, gain staging, unity gain, the difference between dbu, dbV, dbfs, and different types of meters like VU, PPM, etc.

Let me iterate again, using tape out to M10 line in is giving me very low levels. I am used to going from line out on my MM-1 to line in on the m10 using a mono to dual mono cable. I can have levels sit around -12bdfs for dialogue. I know I have less headroom but I know what I'm recording and can ride the gain to get around this. Using the tape out on the MixPre is giving me levels of around -20dbfs for dialogue. I read that for professional recordings this is the norm seeing is we record in 24-bit. For quieter stuff though, backgrounds, wind, birds, etc., I run out of gain on the Mixpre. I don't want to up the gain on the m10 because I need to keep the noise floor as low as possible.

So my questions are, again, should I continue to use the tape out on the MixPre and just deal with very low levels, or should I look at getting a cable made that will give me greater levels but less headroom? I think you tapers don't have a problem seeing as you are dealing with higher SPL sources. Also, though the MixPre and MM-1 are spec'd the same, the MM-1 delivers more gain. I am wondering if there is something wrong with the MixPre I bought as it is used? Seems odd.

It seems my options are: - tape out to line in and deal with running out of gain, pushing up the noise floor, quiet recordings, etc.- using line out to line in via special cable for better levels but less headroom.

This would also help me work out if I need to have a cable made to use my BP4025 when it turns up. Again, will I use tape out and deal with the low levels, or should I get a dual XLR to stereo 3.5mm cable made to use line outputs on MixPre to M10 line in?

If I've got anything wrong or backwards please set me straight. I'm feeling very confused. I do really appreciate the help given so far.

I don't want to up the gain on the m10 because I need to keep the noise floor as low as possible.

Herein lies the problem. It's a common misconception that analog noise linearly increases with gain. In reality, most modern opamps and amplifier designs have lower noise at higher gains.

Jon was correct. You need to increase the gain on the input device (the m10) to maximize your recording levels. Running the dial at 4.5 is too low for the source material you are recording. Don't be afraid to crank the dial on the m10 much higher.

I must admit to feeling a little foolish now, but am happy the problem is so easily resolved. Not sure how I got so confused seeing as I've looked at charts in the past that confirm what you say about less noise at higher gain - fixating on a magical and irrelevant number perhaps

Another simple thing to try: plug into the MIC IN (w/o PIP) on your M10, as recommended other places on TS. Just be careful with your levels coming from your MixPre. I am using a battery box (no preamp), and I do this all the time when I'm recording quiet choral music, and the extra gain gets me a decent level to work with in post. I might need to set the M10's input level around 6 or 7 to get peak levels of -20 to -16, but it's self-noise is low enough that it works out just fine as long as you keep things reasonable.

I did already do a little test plugging into the M10's mic input. The levels were much better but I was concerned I may do some damage though by sending a higher voltage to that circuitry. I gather that isn't the case?

I did already do a little test plugging into the M10's mic input. The levels were much better but I was concerned I may do some damage though by sending a higher voltage to that circuitry. I gather that isn't the case?

I did already do a little test plugging into the M10's mic input. The levels were much better but I was concerned I may do some damage though by sending a higher voltage to that circuitry. I gather that isn't the case?

Cheers, Harry

Going into the mic in should be fine as long as the Plug In Power (PIP) is turned off

Thanks for the help everyone. I am now able to get good levels no matter what the source is by using the information in this thread.

Incidentally, I borrowed a friend's FP24 (his is in new condition), which is identical to my MixPre, and got better levels at the same gain settings. As I found the same thing with my MP-1 I've decided to send the MixPre off for a service. It has a loose pot anyway.

1. First use the 3.5mm consumer line level out (it is labelled tape out) of the MixPre-D > 3.5mm line in of M10

2. Then turn on the tone oscillator/generator of the MixPre-D

3. Set your M10 to REC Pause with 24-bit depth/rate.

4. Calibrate the record level of the M10 to -20 dBFS (this is the unity gain)

That's it, easy as pie you are now properly calibrated!!!

The MixPre-D & MixPre do not use the same 0 dBFS that your recorder uses so 0 dB VU on the MixPre-D is equal to -20 dBFS. Think of this as similar to converting inches to centimeters or fahrenheit to celsius. Different Scales for the same purpose. +20 dB VU on the MixPre-D or MixPre is also equal to 0 dBFS. It is like the K-System K-20/RMS scale of metering allowing a wide dynamic range 20 dB of headroom...

Thus, it is perfectly okay to exceed 0 dBu on the MixPre-D or MixPre unlike the recorders 0 dBFS.

This MixPre-D image shows the tone oscillator/generator turned on (the [~]/SLATE switch)

This image shows proper meter calibration of MixPre-D to Sony M10It is perfectly fine to run the your levels over zero on the MixPre-D. Remember +20dBu is equal to 0 dBFS when properly calibrated, run your levels accordingly.